Download 8.5 Settings - Merging Technologies

18 In The Field
18.3 Non Compensated Telecine at 24 fps
A non-compensated telecine can be used with VCube. A film frame corresponds to a video frame, VCube can playback a 25
fps video capture at 24 fps in order to respect the real duration of the film and to avoid typical audio processing.
After a regular PAL capture, the Composition must be set to 24 fps. The fps info embedded in the Media File can't be
changed from 24 fps to 25 fps to ensure correct playback. But from VCube's Timeline, it's possible to change the playback
speed of the Clip
• Changing Composition frame rate: Settings:Formats & Synchro>Composition Video Format>Composition Frame
Rate
• Changing the Clip playback speed: Double-click on the corresponding clip in the Timeline to display Clips Information.
Then in Clips>Speed, set Payback to 96% (24/25).
1. VCube can still be synchronized to a 25 fps houseclock.
2. Both external (25fps) or internal (24fps) TimeCodes can be dispayed.
VCube is able to play a 24 frames per second Composition, chasing a 25, 29.97 or 30 frames per second TimeCode. VCube
doesn't interpolate frames. It only uses its own ultra precise internal clock to manage the Composition playback. The
external reference TimeCode is only used to synchronize the internal clock.
When the reference TimeCode is different from the Composition TimeCode, it produces artefacts when seeking a particular
frame in the Composition. In the above example, red lines indicate that two different 30 fps TimeCode positions can recall
the same frame in a 24 fps Composition. The blue line does the same for a 25 fps reference TimeCode.
Note that in nominal playback, such artefacts will only appear if clips with mismatched frame rate are included in the
Composition. The playback speed can be edited in Clips Information, allowing perfect playback. This feature is very useful at
25 fps for uncompensated telecine (frame per frame capture on a PAL video).
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